[FFmpeg-devel] [PATCH] intmath: remove av_ctz.

[Ganesh Ajjanagadde]

On Sun, Oct 11, 2015 at 6:04 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> Hi,
>
> On Sun, Oct 11, 2015 at 5:52 PM, Andreas Cadhalpun <
> andreas.cadhalpun at googlemail.com> wrote:
>
>> On 11.10.2015 23:44, Ronald S. Bultje wrote:
>> > It's a non-installed header and only used in one place (flacenc).
>> > Since ff_ctz is static inline, it's fine to use that instead.
>> > ---
>> >  doc/APIchanges       |  3 ---
>> >  libavcodec/flacenc.c |  2 +-
>> >  libavutil/intmath.c  |  5 -----
>> >  libavutil/intmath.h  | 14 ++++++--------
>> >  4 files changed, 7 insertions(+), 17 deletions(-)
>>
>> Should be fine.
>
>
> Thanks, pushed.

Since there is still time, and I did not think of this before, I would
like to replace ff_ctz with ff_ctz32. There are a couple of reasons:
1. It is used with an int32 argument in flacenc.
2. I can do a deBruijn optimization for this as well. With an int also
I could do it, but it would need some ifdefry depending on whether int
is 32 bit or 64 bits.

Let me see if I understand API/ABI with respect to this proposed
change correctly now:
API is not broken, as this is not public.
ABI is broken, since the width of operands to ff_ctz has could change
from 64 to 32 bits.

>
> Ronald
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